THURSDAY, March 8 (HealthDay News) -- The belief that a seasonal flu shot is effective is far more likely to convince health care workers to get vaccinated than reminding them it will help safeguard patients, a new study suggests.

In many developed countries, it's difficult to persuade frontline health care workers to get seasonal flu vaccinations in order to protect patients from the flu, the researchers noted.

To examine the issue more closely, the investigators reviewed 13 studies that included a total of nearly 85,000 health care workers in North America, Europe and Australia.

Overall, doctors were more willing than nurses to get a flu vaccination, according to the study published March 7 in the journal Occupational and Environmental Medicine.

The researchers identified a number of factors that had the strongest influence on health care workers' decision to get vaccinated. All of these factors were associated with a greater-than-double increase in flu vaccination: knowing the vaccine is effective; a willingness to prevent the spread of the flu virus; a belief that the virus is highly contagious and that prevention is important; having a family that is usually vaccinated; and convenient access to vaccination.

Factors that had little influence on health care workers' motivation to get vaccinated included: willingness to protect either themselves or patients at risk of complications if they caught the flu; previous experience with having the flu; being in contact with children; or having direct patient contact.

"Influenza vaccination will only be successful in [health care workers] if they are properly educated and if the vaccine is easily accessible," researchers led by Dr. Giedre Gefenaite, at the University of Groningen in the Netherlands, concluded in a journal news release.

The study authors noted that many differences exist between seasonal flu and pandemic flu, but some of the pro-vaccination factors identified in this study may be important in a pandemic.